1. Field of the Invention
The present invention relates to a drive control integrated circuit that stores in advance the operating pattern of a motor, and controls the operation of the motor based on the stored operating pattern.
2. Description of the Related Art
Conventionally, a dedicated control-use integrated circuit has been offered in order to control the operation of stepping motors. As shown in FIG. 6, in this control-use integrated circuit 20, parameters determining motor operation, such as the quantity of output pulses (drive amount of the stepping motor), a low speed frequency (self-activation frequency), a high speed frequency, and acceleration/deceleration data, are written in a register via a bus interface circuit 22 that interfaces with a control-use external CPU 21. When a start command is supplied via a bus line, pulse signals (CW, CCW) are outputted based on the parameters recorded in the register.
However, in the cases where the operating pattern is complex as with NC devices in machine tools, it is necessary to conduct control based on commands and data from the CPU. In such cases, it is effective to conduct control by means of the aforementioned control-use integrated circuit. However, in the cases where the operating pattern can be specified, for example, in the cases of simple operations such as reciprocal movements between specific points as with conveyance mechanisms, since it is necessary to write in the individual pieces of data from the CPU for each operation. Thus, the stepping motor control load increases for the CPU, and it has been impossible to bring about simplification of the control software.
Moreover, because of the connection of the control-use integrated circuit 20 and the external CPU 21 with the bus, it has been usual to arrange the control-use integrated circuit 20 in proximity to the CPU 21, and to connect it to a motor driver 24 by CW/CCW pulse signals or by pulse signals together with directional signals.
However, when noise interferes with the pulse signals, there is a possibility that operational errors such as positioning deviation may occur, and one must pay careful attention to the wiring to prevent noise interference.
An object of the present invention is therefore to provide a drive control integrated circuit for a stepping motor that eliminates the aforementioned problems, that stores in memory predetermined operating patterns, that can operate the motor merely by selecting a stored operating pattern, that can minimize control by a CPU, alleviate the CPU load, and bring about simplification of the control software, and that enables superior handling.